He captured my feelings exactly. It's not *necessary* to do anything after a wash, especially if you use a wash that has wax in it already. But it's definitely nice to, and if you ask me it makes a pretty big difference in the lifespan of your wax.
Optimum spray wax I believe is designed more as a "true" wax that is sprayed on, so it should give even better durability than something designed to just be a booster wax.